A method for reducing energy consumption and water consumption of a syngas-to-methanol system and a system for producing methanol from syngas

Abstract

The invention relates to the field of industrial methyl alcohol preparation, and discloses a method for reducing energy consumption and water consumption of a system for preparing methyl alcohol by synthesis gas and the system for preparing the methyl alcohol by the synthesis gas. The method comprises the following steps: enabling synthesis gas raw materials to react to obtain a methyl alcohol-containing reaction product; performing primary cooling, secondary cooling and gas-liquid separation on the reaction product; performing flash evaporation on a liquid phase product obtained by performingthe gas-liquid separation; condensing a gas phase product after the flash evaporation is performed, wherein the primary cooling mode is that the reaction product exchanges heat with the synthesis gasraw materials and the liquid phase product which is obtained by the gas-liquid separation; a cooling medium for condensing is provided by the gas phase product obtained by the gas-liquid separation.The system comprises a reactor, a primary cooling unit, a secondary cooling unit, a gas-liquid separator, a flash evaporating tower and a condenser which are connected in sequence; the primary coolingunit comprises a first heat exchanger and a second heat exchanger; a gas phase product outlet of the gas-liquid separator is connected with a cooling medium inlet of the condenser. According to the method and the system, the using amount of steam and recycling water can be reduced.

Description

technical field [0001] The invention relates to the field of methanol production from industrial synthesis gas, in particular to a method for reducing energy consumption of a system for producing methanol from synthesis gas and a system for preparing methanol from synthesis gas. Background technique [0002] Industrial methanol is obtained by the reaction of synthesis gas containing carbon monoxide, carbon dioxide and hydrogen under the action of a certain temperature, pressure and catalyst, and the reaction product is obtained by cooling, gas-liquid separation, filtration and washing, and rectification. Although the heat of reaction has also been properly recovered, for large-scale methanol synthesis units, the energy consumption and water consumption of cooling and rectification are still relatively large (after the reactor outlet preheats the inlet gas, it still needs to consume a large amount of electric energy (accounting for 30% of the total energy consumption of the d...

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Problems solved by technology

[0002] Industrial methanol is obtained by the reaction of synthesis gas containing carbon monoxide, carbon dioxide and hydrogen under the action of a certain temperature, pressure and catalyst, and the reaction product is obtained by cooling, gas-liquid separation, filtration and washing, and rectification. Although the heat of reaction has also been properly recovered, for large-scale methanol synthesis units, the energy consumption and water consumption of cooling and rectification are still relatively large (after the reactor outlet preheats the inlet gas, it still needs to consume a large amount of electric energy (accounting for 30% of the total energy consumption of the device), and at the same time, during flash evaporation, about 0.15t of steam is consumed for each ton of methanol produced, which needs to be further reduced, and the amount of circulating water used to condense the flashed gas is also large

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